如何在Spring Boot中设置在请求中添加新标头

要在Spring Boot中为请求添加新头, 您可以使用HttpServletRequestWrapper和Filter

首先, 创建一个自定义HttpServletRequestWrapper:

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class CustomHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private final String newHeader;

    public CustomHttpServletRequestWrapper(HttpServletRequest request, String newHeader) {
        super(request);
        this.newHeader = newHeader;
    }

    @Override
    public String getHeader(String name) {
        if (name.equalsIgnoreCase("New-Header")) {
            return newHeader;
        }
        return super.getHeader(name);
    }
}

这段代码创建了一个CustomHttpServletRequestWrapper类，它继承自HttpServletRequestWrapper。我们重写了getHeader方法，如果请求中不存在"New-Header"，则返回自定义的新头。

接下来, 创建一个Filter来使用CustomHttpServletRequestWrapper:

import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@Component
public class CustomHeaderFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        String newHeader = "NewHeaderValue"; // 设置新的头值

        CustomHttpServletRequestWrapper customRequest = new CustomHttpServletRequestWrapper(httpRequest, newHeader);
        chain.doFilter(customRequest, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void destroy() {
    }
}

这段代码创建了一个CustomHeaderFilter类，实现了Filter接口。在doFilter方法中，我们将CustomHttpServletRequestWrapper添加到过滤器链中。

最后，在Spring Boot应用程序的配置类中注册该Filter：

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class AppConfig {

    @Bean
    public FilterRegistrationBean<CustomHeaderFilter> customHeaderFilterRegistrationBean() {
        FilterRegistrationBean<CustomHeaderFilter> registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new CustomHeaderFilter());
        registrationBean.addUrlPatterns("/*"); // 适用于所有请求
        return registrationBean;
    }
}

现在，每个经过此CustomHeaderFilter的请求都将包含名为"New-Header"的新头，其值为"NewHeaderValue"。您可以根据需要修改这个值，或者根据实际情况设置其他头信息。